Syntax: Remove recently added <?raw=

This syntax feature was recently added, but even more recently made
redundant with the addition of the __auto_escape_exempt_class feature
which enables instances of a certain class to be exempt from escaping.

This is a far safer way of dealing with outputting HTML as it allows
passing around strings that contain HTML, knowing that they will
bypass escaping no matter how they are echoed.

Generated files will follow in another commit.

We now effectively how removed any new syntactic features and have
only modified the way the VM deals with certain TOKENS.